1. Field of the Invention
The subject matter of this invention is related to circuit interrupters generally and more particularly to covered accessory cases therefore, as well as adjustable under voltage relays, wire retainer collars and one-piece rail attachments.
2. Description of the Prior Art
The present invention provides an improvement over U.S. Pat. No. 4,503,408 issued Mar. 5, 1985 to Mrenna et al entitled "Molded Case Circuit Breaker Apparatus Having Trip Bar With Flexible Armor Interconnection" which is assigned at this time to the assignee of the present application and which is incorporated by reference herein. Accessories for molded case circuit breakers have been known for a long time. Generally in the past the accessories have been mounted externally of the internal portion of the circuit breaker. Molded case circuit breakers are well known in the art. An example of such an accessory is found in U.S. Pat. No. 4,595,812 issued Jun. 17, 1986 to Tamaru et al entitled "Circuit Interrupter With Detachable Optional Accessories". In some cases the accessories are mounted within the internal portion of the circuit interrupter and are protected from interference or dangerous contact by an accessory cover. Examples of such covers are shown in U.S. Pat. No. 4,754,247 issued Jun. 28, 1988 to P. A. Raymont et al entitled "Molded Case Circuit Breaker Accessory Enclosure"; U.S. Pat. No. 4,757,294 issued Jul. 12, 1988 to Todarol entitled "Combined Trip Unit and Accessory Module for Electronic Trip Circuit Breakers" and U.S. Pat. 4,788,621 issued Nov. 29, 1988 to Russell et al entitled "Molded Case Circuit Breaker Multiple Accessory Unit". In all of these examples, the covers can not be removed or opened when the circuit breaker contacts are in the closed position, this provides a safety feature. It would be advantageous, however, if means were found to automatically trip a circuit breaker if the cover is opened and where the same device could be used manually simply to trip the circuit breaker upon desire.
In Europe, molded case circuit breakers are disposed on mounting apparatus called DIN rails rather than in typical load centers as is the common practice in the United States. Therefore, circuit breakers manufactured for use in Europe must be adapted to be interconnected with the DIN rails. An example of such a separate adapter mechanism may be found in U.S. Pat. 5,192,227 issued Mar. 9, 1993 to Bales entitled "DIN Rail Mounting Bracket". Usually the aforementioned DIN rail attachments come in multiple pieces which are assembled onto the back of the circuit breaker for snapping onto the DIN rail at a later time. It would be advantageous if a single DIN rail adapter connection device could be found which was part of the circuit breaker casing.
Many molded case circuit breakers have under voltage trip release mechanisms for causing the circuit breaker to trip open when the voltage on the lines thereof falls below a predetermined limit. The under voltage release mechanism must be adjustable to accommodate many different ranges of voltages and to account for small manufacturing errors when adapted for the use with a single voltage. It would be advantageous if an under voltage release spring adjustment could be found which would simplify the above indicated problem.
Molded case circuit breakers have load and line terminals for interconnection with circuits to be protected or from which power is derived respectively. In order to interconnect the aforementioned terminals with the circuits in question, a collar is provided on the terminal for the interconnection. Such a collar is shown in U.S. Pat. No. 5,206,789 issued Apr. 27, 1993 to Barbry entitled "Terminal Assembly For A Circuit Breaker And Similar Apparatus" assigned on the record to the assignee of the present application. The latter patent is incorporated herein by reference. In order to secure the interconnection between the load conductor for example and the wiring, the wiring and load conductor must be joined by way of the collar. This is a delicate operation requiring the collar to be held precisely in place as the joint is completed. It would be advantageous if a collar arrangement could be found which was self-retaining, that is which was disposed upon the line or load conductor of the circuit breaker in such a manner as to not require separate activity during the connecting operation.